Elevator cars are conventionally formed to comprise a load-bearing frame structure, i.e. a car sling, which comprises a lower horizontal beam system and an upper horizontal beam system, as well as a vertical beam system of a first side and a vertical beam system of a second side, which beam systems are connected to each other so that they form a closed loop, inside which loop is an interior comprised in a car box fixed to the beam systems, which interior can receive goods and/or passengers for conveying them in the interior of the elevator car. Conventionally the car box has been essentially fully inside the aforementioned loop. Also known in the art are elevator cars, in which the beams participating in forming the aforementioned loop are integrated as a part of the wall structures, roof structures or floor structures that bound the interior of the car box. This type of solution is presented in, among others, publication EP1970341A1. In the solution in question, the upper horizontal beam system, inter alia, has been formed from two parallel horizontal beams, instead of one horizontal beam. In the solution presented the horizontal beams are on view, and components external to the elevator car, such as the car suspension means, are disposed alongside them.
The outer surface of the roof of the elevator car can be formed from plates that are firmly and permanently supported on the upper horizontal beam system. According to prior art, there is a separate ceiling panel in the elevator cars, below the upper horizontal beam system and the aforementioned plates forming the outer surface. The ceiling panel can be a single-piece or multi-piece ceiling panel, and the bottom surface of it forms a flat surface bounding the interior of the car. The ceiling panel is generally quite thin in terms of its thickness, e.g. a plate-type structure less than 50 mm thick, into which luminaires are fitted. For the servicing of the luminaires or other components of the roof or for opening the roof trap, the ceiling panel is generally fixed into its position with an openable locking, which can be opened from inside the car for taking the ceiling panel down. The ceiling panel structure has increased the total thickness of the roof structure by the amount of its own thickness plus possible fastening clearances.
One problem with prior-art solutions, among others, has been non-optimal space usage. More particularly the roof structure of an elevator car has not been optimized as an entity sufficiently from the standpoint of space usage. All the essential factors have not been simultaneously taken into account to an adequate extent, more particularly the placement of structures and components external to the elevator car, the space-efficiency and durable construction of the beam system of the frame structure, and the placement of structures and components inside the elevator car. Thus the overall structure of the roof has not been optimal, more particularly the free vertical space inside the elevator car and the free vertical space of the part of the hoistway above the elevator car have not been maximal.